Apparatus including the essential characteristics of the above state kind is the object of the earlier German patent application No. P 28 16 441.2-24. This cited earlier application substantially addresses the following problems:
(1) Achieving a uniform distribution of the mixture of water-air or steam or gas on the slab, with uniform acceleration of the mixture when being sprayed across the slab width.
(2) Spraying into the roller shadows (the triangular space between the slab surface and the roller) to be possible, with a simultaneous attempt to spray away standing water and scale particles from the roller gap by the upwardly blowing effect of the jet of the mixture.
(3) Control of the water flow rate without degrading the spraying profile and while retaining a specific nozzle.
It is the object of the present invention to improve the operation of apparatus of the initially cited kind to such an extent that
(a) a wider, fan-shaped jet achieves a larger heat exchange area, PA0 (b) smaller droplets achieve more intensive cooling and the individual droplets permit faster evaporation, and PA0 (c) the non-evaporated droplets are sprayed sideways above the slab.
Further the nozzle shall be of a simpler design.
These objects are resolved by the present invention essentially in that the cylindrical or substantially cylindrical nozzle housing, which furthermore is provided with a cylindrical feed bore, comprises one prismatically shaped milling at each of two diametrically opposite locations, said milling acting as nozzle discharge and issuing radially into the feed bore.
The invention eliminates the design of the object of the earlier patent application No. P 28 16 441.2-24, namely of mutually nearly opposite nozzle discharge orifices. This elimination makes it possible in an advantageous manner to widen the depth of the jet to the desired magnitude without these jets possibly interfering (as might be the case in the object of the earlier application) with each other.
On account of the design of the invention to so build the nozzles that the jets no longer point toward each other, the nozzle at the same time also becomes simpler in structure. This feature is emphasized furthermore in a preferred embodiment of the invention in that the cylindrical feed bore of the nozzle housing is in the form of a blind hole and comprises a spherically shaped front closure, and in that the sideways millings forming the nozzle discharges issues into the radius of the spherical closure of the blind-hole feed bore of the nozzle housing.
The invention includes another essential feature in that a turbulence disk is mounted within the feed bore of the nozzle housing in front of the nozzle discharges. The turbulence disk appropriately is designed in such a manner that the previously formed mixture of water and air--which when viewed in the radial direction holds a large proportion of water at the center of the mixing chamber than at the edges--will be mixed even more intensively. In this manner the average droplet size can be advantageously decreased.